The present invention relates to chemistry laboratory equipment and pertains particularly to improved couplings for ground glass couplings.
Glassware in the form of vessels, flasks tubing and the like is used extensively throughout chemical laboratories. It is often desirable to set up systems connecting two or more vessels together for the transfer of liquids or gases between vessels. Glass tubing is normally used for such purposes and couplings are typically in the form of tapered ground glass couplings. Such couplings are normally tapered a slight amount typically known as standard taper to insure a secure fit. It is frequently necessary to seal the joint to prevent escape of liquid pressurized gas and the like. Such sealing is frequently accomplished by means of a coating of silicone grease.
The use of silicone grease and other similar sealing methods is undesirable due to the potential contamination thereof and also because such couplings frequently result in the inability to separate the joints. This frequently results in broken vessels and tubing and can result in injury.
The use of silicone grease also makes clean up both time consuming and unpleasant. The grease also tends to cause the adaptors and stoppers to freeze such that they cannot be removed without breakage of the vessel and coupling.
Rotary evaporators use a hollow glass shaft having taper at both ends for coupling to a drive motor and to a glass flask from which a liquid is evaporated. It is usually necessary to establish a good seal between the glass flask and the coupling or shaft. This frequently results in breakage of the flask when attempting to remove it from the shaft. The hollow shaft serves also as a conduit for conveying the vapor from the vessel to a condsensing column. Such glass shafts have the same coupling problems as other ground glass couplings.
It is therefore desirable that an improved evaporator shaft be available.